Analytic code can embed using “Javascript Code” field. Go to Dashboard > Appearance > Theme Options > Advanced > Javascript Code, only javascript code only allowed, without tag.

<javascript>Only code from here</javascript>

Using Old analytic code.

(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
  (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
  m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
  })(window,document,'script','https://www.google-analytics.com/analytics.js','ga');

  ga('create', 'YOUR_UA_NUMBER_HERE', 'auto');
  ga('send', 'pageview');

Using Global Site Tag.

var gtagscript = document.createElement('script');

gtagscript.setAttribute('src','https://www.googletagmanager.com/gtag/js?id=YOUR_UA_NUMBER_HERE');
document.head.appendChild(gtagscript);

  window.dataLayer = window.dataLayer || [];
  function gtag(){dataLayer.push(arguments);}
  gtag('js', new Date());

  gtag('config', 'YOUR_UA_NUMBER_HERE');